A buck regulator comprises an upper switching transistor connected between a voltage input node and a phase node. A lower switching transistor is connected between the phase node and a ground node. An inductor is connected between the phase node and an output voltage node. Circuitry generates control signals to the upper switching transistor and the lower switching transistor responsive to the output voltage and a reference voltage. The control signals to the lower switching transistor selectively turn off the lower switching transistor responsive to a current direction through the lower switching transistor and an indication of whether a voltage error signal has been clamped at a selected level.